Incorrect statement among the following is:

1.	The p-block has 6 columns because a maximum of 6 electrons can occupy all the orbitals in a p-shell.
2.	The d-block has 8 columns because a maximum of 8 electrons can occupy all the orbitals in a d-subshell.
3.	Each block contains a number of columns equal to the number of electrons that can occupy that subshell.
4.	The s- block contains mainly reactive metals.

Ionic radii vary with respect to the following factors:

a. Inversely proportional to the effective nuclear charge.
b. Directly proportion to the effective nuclear charge.
c. Directly proportional to the screening effect.
d. Inversely proportional to the screening effect.
Which of the following pairs of statements is/are correct?
1. a, c
2. c, d
3. a, b
4. c, d

The order of screening effect of electrons of s, p, d and f orbitals of a given shell of an atom on electrons in its outer shell is :

1. s > p > d > f

2. f > d > p > s

3. p < d < f < s

4. f > p > s > d

Among halogens, the correct order of amount of energy released in electron gain (electron gain enthalpy) is:

The period number in the long form of the periodic table is equal to : 

The elements in which electrons are progressively filled in 4f-orbitals are called:

The correct order of size of the given species is: 

The outermost electronic configuration of the last element of the p-block in the 6th period is represented by:

1. $7{\mathrm{s}}^{2}7{\mathrm{p}}^6$

2. $5{\mathrm{f}}^{14}6{\mathrm{d}}^{10}7{\mathrm{s}}^{2}7{\mathrm{p}}^0$

3. $4{\mathrm{f}}^{14}5{\mathrm{d}}^{10}6{\mathrm{s}}^{2}6{\mathrm{p}}^6$

4. $4{\mathrm{f}}^{14}5{\mathrm{d}}^{10}6{\mathrm{s}}^{2}6{\mathrm{p}}^4$